Research newsletter
of the Department of Physics
University of Strathclyde
August 2007

Research newsletter

Welcome to the August 2007 issue of the Departmental Research Newsletter. I am delighted to congratulate Deptartment members on recent awards of an Advanced Research Fellowship (David McKee) and of two international conference prizes (Craig Donaldson and Karen Gillespie). This issue also reports on our recent postgraduate conference and describes research publications and publicity for Francesco Papoff and Aidan Arnold.

Contents
Postgraduate conference at Ross Priory
Signal amplification and control in optical cavities
Advanced Fellowship Award in environmental optics
S cottish lozenges attract publicity
Double prize success for Plasma Division PhD students

[RWM]

Postgraduate conference at Ross Priory

The annual postgraduate conference was held at Ross Priory on August 22nd. Thanks to all participants who made it such a success. Special thanks to Louise for organising the event. Congratulations to all of the students, the standard of whose presentations was extremely high. As a consequence of this the anonymous awards committee judging the best talk was unable to separate the following four people: Alison Craigon, Neal Radwell, Alessio Tierno, and Karen Gillespie. The judges of the best poster agreed that this was presented by Elric Esposito. Congratulations!

[JJ]

Signal Amplification and control in optical cavities

Francesco Papoff and Roberta Zambrini have recently published a paper studying the effects of an off-axis external feedback on a large class of optical cavities and gain media in Physical Review Letters (vol 99 , 063907 (2007), DOI) . The external feedback introduces a spatial nonlocality which leads to new dynamical regimes and enables one to amplify, characterise and control perturbations, either external or intrinsic to the system. Generalizing theoretical methods developed previously (F. Papoff, R. Zambrini, PRL94,243903 (2003)), we show that there are large windows of control parameters where small localized signals can be strongly amplified while the background radiation in other region of the system remains very low. Furthermore, the signal moves across the cavity with transverse phase and group velocities that are easily managed to have the same or opposite signs. It is possible to control signals’ motion

without altering the alignment of the set-up, tuning continuously the group velocity sothat a localized perturbation is steered either towards or against the off-set direction and can even be split into two counter-propagating components, as shown in the figure. These unusual properties open new possibilities for light control and can underpin applications in optical communications, imaging and micromanipulation.

The figure (right) shows a Spatio-temporal diagram for the field intensity |E|2 of a small Gaussian perturbation splitting into two counter-propagating pulses in real a) and Fourier space b).

[FP]

Advanced Fellowship Award in Environmental Optics

Many congratulations to David McKee who has been awarded a 5 year NERC Advanced Fellowship to study optical properties of shelf seas and other optically complex oceanic waters. The award, which is worth £666k, includes funds for shipboard surveys of UK coastal waters as well as facilitating joint fieldwork in the Atlantic Ocean in partnership with the National Oceanography Centre. As well as working with a number of partners in the UK and Europe, David will be collaborating on projects with partners at NASA's Stennis Space Centre and the Scripps Institute of Oceanography in San Diego. The NERC Advanced Fellowship scheme is a highly competitive competition that supports blue skies research by outstanding environmental researchers. Typically less than 8 awards are made each year.

The overall aim of the work is to improve the analysis of satellite remote sensing signals from shelf seas by developing a complete picture of the underlying physics using radiative transfer theory and numerical simulations. David's work will contribute to international efforts to understand air-sea gas exchange mechanisms and output from his research will help to quantify the role of shelf seas in the global carbon cycle. Fieldwork for the Advanced Fellowship will commence in January 2008 when he is scheduled to take part in a UK-SOLAS cruise investigating the impact of Saharan dust deposits on the formation of phytoplankton blooms in the Atlantic Ocean between the Canary and Cape Verde Islands. An improved understanding of the range of optical complexity of natural waters will make a key contribution to effective monitoring of oceanic processes from space.

(Congratulations also to David and Gillian on the birth of their latest young'un!)

[DMcK/RWM]

Scottish Lozenges attract publicity

Work by Aidan Arnold and collaborators at Glasgow on optical ferris wheels has recently been published in Optics Express (vol 15, p8619, 2007) and profiled in the AIPs Physics New Update.

" A new form of optical lattice, a ring-shaped lattice which spins about, has been planned by physicists at the University of Glasgow and the University of Strathclyde. In an optical lattice a web of laser beams can hold a collection of atoms in place in free space. If the frequencies of the two holographically generated laser beams are different, the resultant lattice can be spun about." More details.

Aidan's work is about to be even more in the public eye, as the cover of the new 2007-8 Institute of Physics diaries (due to be released with the September issue) is adapted from a figure from one of his earlier papers too!

[RWM]

Double Prize Success for Plasma Division PhD students

Two of the PhD students in our Plasma Division have excelled by winning prestigious prizes at international conferences, as shown in the photographs above.

Karen Gillespie won the prize for the best student poster paper at the International Conference in Phenomena in Ionized Gases that was held in Prague, 15-20 July 2007. There were over 600 participants attending this conference and a panel of 10 international judges judged the poster papers, including asking questions of the student presenters. The prize included a subscription to a plasma journal, as well as two books.

Craig Donaldson won the prize for the best student oral paper at the IEEE International Conference on Plasma Science held in Albuquerque, USA in June 17-22, 2007, which had over 1,000 participants. A panel of international judges listened to the papers and then asked questions of the short-listed presenters. The prize included a cheque for $400.

Both Karen and Craig are PhD students working on different research topics within the ABP research group of the Plasma Division. Unconnected with their prize-winning research activities, Karen and Craig are planning to get married
to each other in February next year. Congratulations to them both.

[ADRP]

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